The pump control apparatuses used in similar applications include the apparatus disclosed in patent reference literature 1. The apparatus disclosed in patent reference literature 1 controls an actuator-drive hydraulic pump and a fan-drive hydraulic pump, both driven by an engine, as described below. Namely, it calculates a required rotation speed for a cooling fan based upon the cooling water temperature or the lubricating oil temperature and controls the output flow rate at the fan-drive hydraulic pump in correspondence to the required rotation speed. Then, it calculates the intake torque of the fan-drive hydraulic pump based upon the output flow rate and adjusts the intake torque of the actuator-drive hydraulic pump in correspondence to the extent to which the intake torque of the fan-drive hydraulic pump is increased/decreased. The excess intake torque that is not used at the fan-drive hydraulic pump is thus allocated to be used as the intake torque at the actuator-drive hydraulic pump.
Patent reference literature 1: Japanese Laid Open Patent Publication No. 2005-188674